# Category : Science and Education

Archive : CHSOLV.ZIP

Filename : CHSOLV.DOC

CheapSolver - General Purpose Equation Solver

Version 1.0 - April, 1989

Leander Software & Consulting

15072 E. Mississippi Ave

Box # 51

Aurora, CO 80012

Copyright (c) 1989 - Leander Software & Consulting

INTRODUCTION

CheapSolver is a shareware program which will solve mathematic

equations and was written to help high school and college

students survive their math classes. While taking Calculus and

helping my wife with Algebra, I started looking for programs

which would allow us to check our homework and ease the drudgery.

The commercial programs were far too expensive and complex for

our needs and, at the time, there was nothing in the shareware

catalogues that would help either. Being the ambitious fool that

I am, I decided to write one myself. The result is CheapSolver.

OPERATION

CheapSolver will solve an algebraic equation with one unknown

variable using numeric methods. The formula can contain up to 20

variables and can use any of sixteen predefined math and trig

functions. After entering the equation, the program will issue a

prompt for each variable specified, enter either a numeric value

or a question mark (?) to specify the unknown variable. The

program will next request the range in which to search for

solutions, then after a short wait will list the solutions found

(up to 20). At this point, you may print the results, start over

or exit the program.

To start the program, enter

A>chsolv

Equations are entered in a form similar to the BASIC language.

Variables can be up to four characters long and must start with

a letter (A..Z), followed by letters or numbers and are converted

to upper case before the formula is evaluated.

Arithmetic operands are:

+ add

- subtract

* multiply

/ divide

^ exponentiation

The following math and trig functions may also be included:

Arithmetic Functions

ABS (x) - Absolute Value

INT (x) - Integer portion of argument

SGN (x) - Sign of argument (returns -1, 0 or +1)

SQR (x) - Square Root

Logarithmic Functions

EXP (x) - Exponent of e ( e ^ x )

LNE (x) - Natural Logarithm (base e)

LOG (x) - Common Logarithm (base 10)

Trigonometric Functions (all trig functions based on radians)

ACS (x) - ArcCosine

ASN (x) - ArcSine

ATN (x) - ArcTangent

CSC (x) - Cosecant

COS (x) - Cosine

COT (x) - Cotangent

SEC (x) - Secant

SIN (x) - Sine

TAN (x) - Tangent

Parenthesis () and spaces may also be included as needed. The

formula is evaluated from left to right using the standard order

of precedence (exponentiation, multiplication/division,

add/subtract).

Examples of valid equations:

2*x-3 = 5

y = pi/2 + cos (3*x)

x^2 - 2*x + 4 = 0

Once the equation is interpreted, prompts will be issued for each

variable found. Enter a numeric value for each known variable

and a question mark (?) for one the unknown variable. Up to 20

variables can be used but only one variable can be unknown.

Numbers can be values from -10^38 to +10^38; make sure that any

computations do not exceed this range or the program will

terminate.

A prompt will be issued requesting the minimum and maximum values

that can be used for the result. Since many equations (such as

trig functions) can produce an infinite number of results, this

range limits the number of values found. The first 20 results

will be printed.

To exit the program, select 'Q' (quit) after the results are

printed or press enter when the program prompts for the next

equation. To use the same equation several times, enter 'same'

when the equation is requested.

REGISTRATION

This program is distributed using the "shareware" concept. You

may copy it and distribute it to others for use on a trial basis

as long as the program file (CHSOLV.EXE), this documentation and

the registration form are included without any modifications. It

may also be put on bulletin boards and distributed through any of

the shareware catalogues.

If you find this program useful, you are encouraged to become a

registered user. For the $20.00 registration fee, you will

receive the full instruction manual and the most recent version

of the program. To print the registration form use the following

DOS command:

a> type chorder.frm >prn

PROGRAM PROBLEMS

If you discover a formula that cannot be solved by this program

(within the realm of real numbers {-10^38 to < 10^38}) please

print the results and send them to the address listed on the

registration form with an explanation of what the correct answer

is. We want to know of problems even if you are not a registered

user.

LEGAL STUFF

Use of this software signifies your agreement that Leander

Software & Consulting grants you a licence to use the CheapSolver

program "as is" with no guarantees. The program may also be

copied and distributed according to the restrictions stated

above. We will not be liable for any damages or loss of income

caused from using the program and cannot guarantee the accuracy

of any program results.